Friday, January 12, 2007

Rosenbloom's law of wind turbine output

Eric Rosenbloom, currently the president of National Wind Watch, has observed from cumulative output vs. time graphs (see the samples from Germany, Ireland, and Denmark) the following:
Whatever the capacity factor, or average output over a period of time, any turbine or aggregate of turbines generates at or above its average rate only 40% of the time.
A recent illustration of this law is the output from the 240-MW Maple Ridge wind energy facility in Lewis County, N.Y., as compiled by Richard Bolton:


For this period from July through September 2006, the output represented 25% of capacity, or an average rate of 80 MW. As the graph shows, the facility produced at a rate of 90 MW or more only about 520 out of the total 1,883 hours of data collection, i.e., about 28% of the time. Adding the number of hours that it generated at 80-90 MW brings the time figure close to a third.

wind power, wind energy, wind farms, wind turbines